Profound CP was defined as a GMFCS level of 4 or 5. Children who were defined as GMFCS level 1 were excluded and were included in the minimally impaired group. Hearing impairment was defined as requiring amplification. Visual impairment was defined as blind with no functional vision in 1 or both eyes. Cognitive delay was defined as a DQ score <70; if the child was unable to complete the KSPD assessment, the pediatrician estimated the child’s developmental level as delayed or not. In cases judged as delayed, the developmental level was assumed to be equivalent to a KSPD DQ of <50. NDI was defined as any of the following: CP with a GMFCS level of 2 to 5, hearing impairment, visual impairment, or DQ score <70. Profound NDI was defined as profound CP and/or a DQ score of <50. Children with an unknown CP level were classified into profound impairment.